Soap bars have been employed in washing a human body and doing laundry for some time. Before the advent of washing machines which dictated the employment of a detergent material and powder, disintergratable bricket or liquid forms, laundry was washed with "laundry soap" bars made from suitable soaps of higher fatty acids such as sodium soap of mixed tallow and rosin fatty acids. Such laundry soap bars were especially suitable for rubbing onto badly stained or soiled portions of fabrics being laundered, as on a wash board, to deposit a high concentration of soap on the soiled area and then providing a mechanical means for applying energy to said surfaces to assist in removing the stains and soils.
Despite the fact that after the introduction of synthetic organic detergents and washing machines, the amount of soap employed for laundry use diminished greatly, with soap based laundry bar being replaced mostly by synthetic organic detergent compositions in powder, liquid or other suitable forms, laundry soap and detergents in bar forms are still preferred by some consumers, especially in certain areas of the world.
Several detergent laundry bars based on alkyl benzene sulfonate detergents have been successfully marketed. They have been characterized as the equivalent in detersive action of powdered laundry detergent based on similar alkyl benzene sulfonates and are considered by many consumers to be more convenient to use. To use them does not require a washing machine as previously indicated, the bar form of the product allows it to be used in such a manner that a comparatively high concentration of detersive material may be readily applied to a heavily stained soiled area with accompanying physical force or energy as on a wash board so as to readily loosen and remove soil or stain.
When the sodium alkyl benzene sulfonate is partially or fully substituted with coco fatty alcohol sulfate as the required surfactant in a detergent laundry bar formulation, the resulting product is deficient in physical hardness during processing, is brittle upon aging and is used up faster during washing by hand.
One solution to the breakage problem is disclosed in U.S. Pat. No. 4,543,204 which teaches the incorporation of higher fatty acids into a bar formula to counteract the tendency of higher fatty acids alcohol sulfate laundry bars to crack or break during storage and shipment and, also mentions the fact that fatty acids improves the foaming characteristics of the fatty acid alcohol sulfate bars. However, that requires the addition of a material to the formula which is not a detergent or builder and which is comparatively expensive. The present invention is of a detergent laundry bar of acceptable laundry bar properties which is environmentally acceptable biodegradable, and does not crack or break to an excessive extent while being stored or in shipment.